FIG. 7 shows the structural drawing of the pump station wherein a conventional vertical axis pump is installed. The discharge elbow 12 is mounted onto the 1st floor level 10, and column pipe 16, impeller casing 18 as well as the suction bell 20 are suspended vertically as a single body from the discharge elbow 12 into the suction water tank 14, provided below the 1st floor level 10. The reduction gearbox 24, and the driver 26 coupled to it are mounted onto the 2nd floor level 22 provided above the 1st floor level 10, and the pump shaft 28 coming out of the outer wall of the discharge elbow 12 in the vertical direction is coupled by use of a suitable coupling to the output shaft of the reduction gearbox 24. Based on drive from the driver 26, the corresponding rotational speed(RPM) being reduced by the reduction gearbox 24, the pump shaft 28 is driven by this reduced rotational speed, resulting in water being pumped up by the vertical axis pump.
Regarding the installation construction of conventional vertical axis pump, a pump room of two floor construction is required wherein the discharge elbow is mounted onto the 1st floor level 10, and the reduction gearbox 24, as well as the driver 26 are mounted onto the 2nd floor level 22 provided above the 1st floor level 10. Hence, the construction cost of such a pump room was high. In addition, as the installation height of the vertical axis pump is very high, a crane of high lift was necessary for assembly work, which in itself made assembly work very troublesome. Furthermore, optional equipment such as cooling arrangement for cooling of lubricating oil of reduction gearbox 24 was also required.